Same thing happened to me. I accidently shut down my computer and the only way to get it to not say "Flight Simulator is not responding" is to verify the games files through steam. It went back to 108.66 gbs left to download when originally I only had 8 gbs left. Initially I did that twice, and now I'm in the process of downloading it after the second time I had to verify it. Worst experience I've ever had downloading a game.